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PubMed2026

Avian egg incubation period: Revisiting existing allometric relationships via surface area-to-volume ratio of an egg.

The incubation period (I) for bird eggs varies among species and is used in establishing allometric relationships. Research on variations in I shed light on the evolutionary mechanisms that gave rise to the differentiation of embryonic development in distinct taxa of birds. Here, using a sampling of 444 images from 444 avian species, 89 families and 30 orders, we calculated their major geometric dimensions: volume (V) and surface area (S). An assessment of the relationship between I and the measured and calculated egg parameters demonstrated the closest and most significant correlation (R = -0.760) between I and the S/V ratio that was adopted as a conditional indicator and reflects the embryo's metabolic rate. Approximation of the values of these parameters made it possible to derive a power-law dependence for the prediction of I depending on the S/V value of a particular egg (R2 = 0.757). The prediction accuracy was higher (R2 = 0.783) if the eggs of the family Procellariiformes (petrels), whose I value is characterized by a longer time, were removed from the general sampling computation. We conclude that the value of the S/V ratio can characterize both the metabolism of an embryo and the conditional thermal conductivity of an egg, which aids in ensuring the temperature regime of egg incubation.

Animals↗
PubMed2025

Uncovering parental exposure risks of TCPP: Impaired development and metabolic homeostasis in zebrafish offspring.

As brominated flame retardants are phased out, tris (1‑chloro-2-propyl) phosphate (TCPP), a phosphorus-based flame retardant, has emerged as a prominent detectable flame retardant in the environment. However, TCPP has been found to exhibit endocrine-disrupting effects on organisms, raising significant safety concerns. In our study, we utilized the zebrafish model to explore the toxic effects of parental TCPP exposure on offspring and uncover its regulatory mechanisms through metabolomics analysis. Moreover, the impact on the nervous system and lipid metabolism was examined through behavioral analysis and specific staining. Our findings demonstrated that both embryonic and parental TCPP exposure induced developmental disorders in larvae, along with decreased locomotor activity and disordered lipid metabolism homeostasis. Parental exposure to TCPP, exhibiting stronger developmental toxicity than direct embryonic exposure, notably led to reductions in crucial energy substrates such as amino acids and carbohydrates. Meanwhile, embryonic TCPP exposure primarily affected the endogenous lipid-related metabolites including phospholipids, lipid-soluble vitamins, steroids and fatty acids, promoting lipid accumulation in larval liver and subcutaneous tissue. What's more, continuously parental and embryonic exposure showed the most pronounced effects on zebrafish development and metabolic regulation. Our study highlights the risk posed by parental exposure to TCPP on offspring zebrafish, underscoring the need for comprehensive consideration of the impact from parental exposure in pollutants regulation.

Animals↗
PubMed2026

Maternal transfer of nonylphenol drives oxidative, immune, and epigenetic dysregulation in zebrafish offspring.

Nonylphenol (NP), a widespread surfactant and endocrine-disrupting pollutant, poses significant ecological and public health risks globally; however, its transgenerational effects remain poorly understood. Using zebrafish (Danio rerio), we compared chronic maternal NP exposure (50 and 100 µg/L, 28 days) with acute embryonic exposure (0.22 µmol/L) during 0-3 days post-fertilization (dpf) to delineate mechanistic differences in toxicity. Maternal NP exposure produced severe developmental defects in offspring, including edema, axial curvature, impaired swim bladder inflation, reduced growth, cardiac dysfunction, and decreased viability. These phenotypes were accompanied by systemic molecular disruptions including oxidative stress, altered estrogen receptor (ER) expression, dysregulated mitogen-activated protein kinase (MAPK) signaling, and suppressed innate immune response characterized by attenuated neutrophil/macrophage density, reduced CD68 and complement protein C3 expression, diminished nitrite load, and downregulation of pro-inflammatory mediators at both transcript and protein levels. Maternal exposure further induced apoptosis and persistent epigenetic reprogramming (alterations in DNA methylation and histone-modifying enzymes), hallmarks of transgenerational toxicity. In contrast, direct embryonic NP exposure elicited morphological abnormalities without significant lethality, accompanied by induction of pro-inflammatory cytokines, nitric oxide (NO) synthesis, and MAPK activation, reflecting an augmented inflammatory response. These mechanistic contrasts reveal that maternal NP exposure is a potent driver of systemic, heritable molecular reprogramming, whereas embryonic exposure triggers acute inflammatory pathways. Together, our findings underscore the global relevance of NP as a transgenerational toxicant, advocating for its urgent inclusion in ecotoxicological risk assessments and regulatory frameworks.

Animals↗
PubMed2026

Morphological changes and transcriptomic insights into skeletal development of embryos and larvae of the sea urchin Strongylocentrotus intermedius.

To explore morphological features and molecular dynamics underlying skeletogenesis in the sea urchin Strongylocentrotus intermedius, we conducted combined morphological observation and comparative transcriptome analyses across representative embryonic and larval developmental stages. Morphological results showed that triradiate spicules first emerged at the gastrula stage. The 8-arm pluteus stage was identified as a key phase for skeletal remodeling, during which new three-radiate crystals transformed into complex stereoscopic ossicles including tube feet, spines and test plates. Transcriptomic data indicated that most differentially expressed genes (DEGs) were downregulated from the blastula to gastrula. The altered expression of basal metabolic genes and extracellular matrix genes including Colp2α and calm may be correlated with the linear mineralization of early spicules, which potentially reflects an energy adjustment pattern in developing larvae. During the transition from 6-arm to 8-arm pluteus, expression changes of calmodulin-like, Colp2α and SISin18G001660 suggest potential associations with regional calcium deposition and modifications of skeletal matrix properties. This work systematically characterizes morphological traits and transcriptional dynamics of skeletogenesis in S. intermedius. Its early spiculogenesis follows the conserved developmental pattern of echinoderms, while massive formation of stereoscopic ossicles occurs at the 8-arm pluteus stage. Stage-specific transcriptional changes across key larval skeletogenic stages are uncovered, offering transcriptomic resources for functional verification of skeletal regulatory genes.

Animals↗
PubMed2026

The HOXA gene cluster: a critical regulator in bone-related disorders.

BACKGROUND: Skeletal homeostasis relies on the dynamic balance between bone formation and bone resorption. The disruption of this balance acts as the central pathological mechanism of multiple metabolic bone diseases including osteoporosis, and is closely correlated with the progression of various other bone-related disorders. As pivotal transcription factors regulating embryonic development and cell fate, the homeobox A (HOXA) gene family plays an essential role in skeletal physiological and pathological processes. METHODS: This review systematically summarizes recent research advances of the HOXA gene family in bone-related diseases, concludes the evolutionarily conserved regulatory patterns of HOXA members, and clarifies the molecular mechanisms by which HOXA genes mediate bone metabolic disorders and the occurrence as well as development of bone diseases. RESULTS: Accumulating evidence demonstrates that HOXA family members present complex functions and strong heterogeneity in bone-related diseases. They participate in the pathogenesis of bone diseases via three evolutionarily conserved regulatory manners: determining regional patterning, modulating signaling pathways, and integrating epigenetic and non-coding RNA (ncRNA) regulatory networks. CONCLUSION: Further exploring the underlying mechanisms of the HOXA family in bone-related diseases provides novel insights into the pathogenesis of bone disorders. Meanwhile, it also supplies solid theoretical basis and potential therapeutic targets for the development of novel HOXA-targeted therapeutic strategies against bone diseases.

Humans↗
PubMed2026

Studies on functional differentiation of xpr1a and xpr1b genes in zebrafish.

Xenotropic and polytropic retrovirus receptor 1 (XPR1) is known to be involved in various biological processes, including phosphate homeostasis, cellular signaling, brain and vascular mineralization, whereas its specific contribution to bone development remains incompletely characterized. Due to genome duplication in teleosts, zebrafish Danio rerio possess two paralogous genes of XPR1 namely xpr1a and xpr1b, whose functional divergence remains unclear. The amino acid sequence similarity between zebrafish xpr1a and xpr1b was 83.26%. In situ hybridization demonstrated overlapping localization in the head and spinal cord at 24-48 hpf, while diverged by 72 hpf, with xpr1a becoming restricted to the head while xpr1b persisted in both regions. CRISPR/Cas9 was used to generate xpr1a and xpr1b mutants. The xpr1a mutants are comparatively healthy, viable but with mild growth reduction, whereas the xpr1b mutants display high mortality, reduced body length and severe vertebral deformities. Interestingly, all the double mutants died at the embryonic stage. Moreover, to further investigate the molecular and regulatory mechanisms, we conducted comparative transcriptome analysis on bone and brain tissues from xpr1b+/+ and xpr1b-/- zebrafish. In bone tissue, 6749 DEGs were identified, comprising 3846 upregulated and 2903 downregulated genes. These DEGs were mainly enriched in the MAPK signaling pathway, Wnt signaling pathway, cysteine and methionine metabolism, and ECM-receptor interaction. RT-qPCR validated results showed that seven osteogenesis-related genes (col1a1a, sp7, runx2b, col1a2, col1a1b, alp1 and entpd5), and two phosphate homeostasis related genes (slc20a2 and pdgfba), which are essential for skeletal mineralization and phosphate homeostasis, exhibited significantly downregulated expression in bone tissue of xpr1b mutant zebrafish. These results highlight the pivotal role of xpr1b in regulating skeletal mineralization and phosphate metabolism, thereby elucidating the functional specialization of XPR1 paralogs while providing a theoretical basis for understanding bone developmental mechanism in teleost vertebrates.

Animals↗
PubMed2026

Genome-wide characterisation of the myosin light chain gene family in Chinese perch (Siniperca chuatsi) and its expression patterns in muscle fibre types and injury response.

The Class II myosin light chain (myl) genes in Chinese perch (Siniperca chuatsi) have not yet been systematically characterised, and relationships with muscle fibre specification, development, and injury-associated remodelling remain unclear. In this study, fast and slow muscle fibres were initially distinguished using myofibrillar ATPase histochemistry. Subsequently, genome-wide mining identified 16 Class II myl genes, comprising eight essential and eight regulatory light-chain subunits. Their conserved-domain features, chromosomal distribution, phylogenetic relationships and expression profiles were analysed. Transcriptomic profiling showed that summed myl transcript abundance was higher in fast muscle than in slow muscle, accounting for 67.2% of the pooled myl transcript pool across the two muscle types (paired t-test, raw P = 0.036). mylpfa, myl1 and mylz3 were the major fast-muscle-associated genes, whereas myl10, myl2b and myl13 were preferentially expressed in slow muscle at the transcript level. These patterns support these genes as candidate fibre-type-associated expression markers. Developmental profiling identified stage-associated myl expression patterns, including a possible expression shift between mylpfb and mylpfa. In the descriptive injury-repair time course (d0-d7), FPKM profiles indicated that fast-muscle-associated genes (mylpfa, mylz3 and myl1) were lower at d1 and recovered by d3, whereas several slow-muscle-associated genes showed biphasic transcript-level increases. The slow-muscle-associated RLC gene mylpfb showed a delayed expression peak at d7. Notably, the embryonic isoform myl6l showed a modest increase from approximately 2 FPKM at d0 to 4-5 FPKM after injury, suggesting a possible injury-associated expression pattern that requires further validation. Together, these findings provide a genome-wide description of the Chinese perch myl gene family and identify candidate fibre-type-associated genes and descriptive injury-associated isoform expression patterns.

Animals↗
PubMed2026

Genome-wide identification and expression analysis of the CREB/ATF family and its potential role in melanogenesis in the Manila clam (Ruditapes philippinarum).

Ruditapes philippinarum is an economically important bivalve species in China, and shell color is a trait of ecological and commercial significance. Melanin is a key determinant of shell color, and members of the CREB/ATF family have been reported to participate in melanogenesis in other organisms. In this study, members of the CREB/ATF family were systematically identified at the whole-genome level based on genomic and transcriptomic datasets, followed by analyses of their phylogenetic relationships, gene structures, and expression patterns. A total of six CREB/ATF family members were identified and classified into five subfamilies. Expression profiling and RT-qPCR validation revealed that most CREB/ATF genes were highly expressed in the mantle and displayed clear differences among shell-color phenotypes. Except for RpATF4 and RpCREBZF, most members exhibited relatively high expression levels in dark-colored shell strains, particularly in black and zebra-striped clams. Moreover, most genes showed low expression during early embryonic and larval stages but increased expression at the single-siphon spat and juvenile stages. These results suggest that the CREB/ATF family may be involved in melanin-associated shell-color regulation in R. philippinarum, providing important candidate genes and a theoretical basis for further elucidating the molecular mechanisms of shell-color formation in mollusks.

Animals↗
PubMed2026

Perinatal depression, maternal thyroid status and fetus/infant health and development: A systematic review.

BACKGROUND: Thyroid hormones are known to influence both maternal depression and child developmental outcomes, while maternal depression independently affects child outcomes. The potential interaction between thyroid dysfunction and depression in shaping child development remains insufficiently explored. The present study addresses such interplay. METHODS: Following PRISMA 2020 and JBI guidelines, three databases were searched through December 2025 for primary studies on maternal thyroid status, perinatal depression, and child development. Risk of bias (RoB) was assessed using validated tools. Due to clinical and methodological heterogeneity, data were synthesized narratively following SWiM guidelines. RESULTS: Eleven studies were included. Beyond independent risks for preterm birth and behavioral problems, limited evidence supports a synergistic model, while most studies likely reflect the simple co-occurrence of risks. Maternal thyroid peroxidase antibodies (TPO-Ab) were associated with child externalizing problems exclusively in the presence of clinical depression. High depressive symptoms also attenuated the cognitive benefits of prenatal iodine supplementation. Thyroid status appears to function as a risk moderator rather than a mediator. However, 50% of observational studies presented high RoB, primarily due to participant attrition. CONCLUSION: Findings are still scarce to support a synergistic risk model where specific maternal thyroid parameters (i.e. thyroid autoimmunity and iodine status) may moderate the impact of depressive symptoms on child development. Despite the high RoB in half of the studies, results highlight the need for integrated screening protocols. Simultaneously assessing mental health and thyroid status may optimize risk stratification for high-risk mother-infant dyads.

Female↗
PubMed2026

Genomic identification and functional characterization of the nuclear receptor gene family in relation to sex determination and gonad development in the Pacific oyster (Crassostrea gigas).

Nuclear receptors (NRs) are a large superfamily of transcription factors that control a wide range of physiological processes by modulating the expression of downstream target genes. Numerous studies have confirmed that NR family members play critical and conserved roles in sex determination and gonadal development across metazoans. However, in mollusks, systematic characterization of NRs and their potential functions in gonadal regulation remain largely unexplored. In this study, 46 NR gene family members in the Pacific oyster (Crassostrea gigas) were identified and assigned to eight subfamilies. All NR family members contain at least one of the two core domains (DNA-binding domain, DBD; ligand-binding domain, LBD), and conserved exon-intron structures were observed within the same subgroup, indicating their evolutionary conservation. Furthermore, expression profiling revealed high expression of CgNR2F, CgNR5A1-1, and CgNR0B1 in undifferentiated gonads, suggesting their potential involvement in sex determination. CgNR1A and CgNR2E5 were specifically expressed in female gonads and exhibited female-biased expression patterns, indicating a putative role in ovarian development. Moreover, CgNR3A and CgNR3B showed high expression levels during the undifferentiated stage and early male development stage, implying their possible participation in male gonadal development and gametogenesis. These results expand the understanding of the NR gene family in C. gigas and help elucidate the potential functions of NR genes in sex determination and gonadal development.

Animals↗
PubMed2026

The circadian clock proteins PRR modulate root hair development via the RHD6/RSL module in Arabidopsis.

Root hairs, derived from trichoblasts, are critical for plant growth and environmental adaptation. Although environmental cues are known to influence root hair development, how endogenous timing systems such as the circadian clock integrate into the core transcriptional network governing root hair formation remains unclear. Here, we show that the circadian clock-associated protein PSEUDO-RESPONSE REGULATOR5 (PRR5) physically interacts with ROOT HAIR DEFECTIVE6 (RHD6) and RHD6 LIKE1 (RSL1), two basic helix-loop-helix transcription factors essential for root hair initiation. Genetic analyses suggest that PRR proteins contribute to root hair development under long-day conditions in Arabidopsis thaliana. Simultaneous disruption of PRR5, PRR7, and PRR9 results in defective root hairs, whereas PRR5 overexpression markedly increases root hair density and length. Transcriptomic and RT-qPCR analyses reveal that PRRs enhance the expression of RHD6, RSL1, and multiple downstream root hair-responsive genes, while modulating their temporal expression patterns. Furthermore, PRR5-mediated root hair promotion requires RHD6/RSL1, and PRR proteins enhance RHD6-dependent activation of the RSL4 promoter. PRRs also contribute to root hair development under phosphate-deficient and salt-stress conditions. Together, these findings establish a molecular framework in which PRR proteins regulate the RHD6/RSL network to coordinate root hair development and environmental responses.

Arabidopsis↗
PubMed2026

Transcranial Photobiomodulation Variables Assessment Battery: Development and Validation.

Transcranial photobiomodulation (tPBM) response variability is partly driven by biophysical characteristics such as skin tone and hair properties that attenuate photon penetration, and by lifestyle factors including sleep quality, alcohol use, and nicotine consumption that disrupt the mitochondrial and vascular pathways on which tPBM acts. To date, no validated self-report tool exists to capture these moderators systematically. To address this gap, the tPBM Variables Assessment Battery was developed and psychometrically evaluated. It integrates adapted versions of established measures (Brief Pittsburgh Sleep Quality Index, E-cigarette Dependence Scale, Hair Scale Assessment PRO, Monk Skin Tone Scale, and Heaviness of Smoking Index), validated wellbeing evaluators (Ryff's Psychological Wellbeing), and custom measures (Hairstyle Classification, Hair Color Classification). Face and content validity met recommended expert thresholds, internal consistency was acceptable across adapted subscales, and criterion validity analyses confirmed meaningful associations between the lifestyle components and PROMIS-10 global health outcomes. The battery is low-burden, digitally deployable, and psychometrically defensible, offering a practical tool for characterizing the variables most likely to moderate tPBM response in home-use studies.

Humans↗
PubMed2026

Genital surgery in children with differences of sex development (DSD): Strengths and concerns across diverging regulations in four European countries.

Differences of Sex Development (DSD) is a collective term for a heterogeneous group of rare congenital conditions characterized by atypical genetic, gonadal, or genital sexual development. The treatment of children with DSD, particularly the indications for and timing of surgical interventions, has been the subject of debate for decades. In recent years, social developments emphasizing children's rights to self-determination and bodily integrity, along with increasing societal acceptance of atypical sex characteristics, have encouraged a more cautious approach toward early genital surgery in children with DSD. In 2019, the European Parliament adopted a resolution urging Member States to enact legislation prohibiting elective genital surgical interventions on intersex infants and children. Since then, several countries have indeed implemented restrictive measures, including legal bans on early surgical procedures. In this paper, we share the experiences and insights gained in recent years as pediatric urologists working in four neighboring countries in multidisciplinary university centers specializing in DSD care and research. We focus on current approaches to the care of children with DSD, the evolution of relevant national policies over time, and the nature and impact of recently introduced restrictive regulations on early surgical interventions. By presenting perspectives from pediatric urologists across these four countries, we aim to contribute to ongoing discussions on the alignment and refinement of surgical treatment practices for children with DSD.

Humans↗
PubMed2026

Effects of rumen fluid transplantation on longissimus dorsi muscle development in Xizang sheep: An association analysis based on transcriptomic and serum metabolomic profiles.

This study aimed to investigate the effects of rumen fluid transplantation (RFT) on the growth and development of the longissimus dorsi muscle in female Xizang sheep. After RFT, muscle lightness differed significantly between the two groups, with the LDC group showing significantly higher lightness than the LDT group. In contrast, no significant differences were observed between groups in other muscle phenotypic traits, including drip loss, pH, cooking loss, shear force, redness, and yellowness. Antioxidant-related indices (SOD, GSH-PX, MDA, CAT, and T-AOC) also showed no significant differences between groups. Histological analysis revealed that muscle fiber length, width, and density were significantly greater in the experimental group than in the control group. Transcriptomic analysis identified 515 differentially expressed genes (DEGs), of which 419 were downregulated. KEGG analysis indicated that genes involved in muscle development-related pathways, such as cell adhesion and the PI3K-Akt signaling pathway, were predominantly downregulated. Key serum metabolites (L-kynurenine, IPA, allantoin, and propionylcarnitine) showed highly significant positive correlations with muscle fiber growth indices. In contrast, metabolites such as l-carnitine, acetylcarnitine, and citrulline were negatively correlated with muscle fiber growth, but positively correlated with the expression of muscle structure-related genes (COL11A1 and EFNA5) and with meat lightness. Overall, this study provides new insights into the potential molecular basis by which RFT influences muscle growth and development. However, the mechanisms by which RFT affects muscle development and meat quality-related traits remain unclear and warrant further investigation.

Animals↗
PubMed2026

Pathogenic Variants in HEPACAM Alter Protein Localization and Interactome in Astrocytes of the Developing Mouse Cortex.

Megalencephalic leukoencephalopathy with subcortical cysts (MLC) is a rare leukodystrophy characterized by early-onset macrocephaly, white matter edema, seizures, and motor and cognitive decline. Approximately 25% of MLC patients carry HEPACAM pathogenic variants, many of which are dominant missense variants causing remitting MLC Type 2b. HEPACAM encodes hepatic and glial cell adhesion molecule (hepaCAM), also known as GlialCAM, an astrocyte-enriched transmembrane protein with important roles in astrocyte territory establishment, gap junction coupling, branching organization, synaptic function, and development of the gliovascular unit. The molecular mechanisms through which pathogenic variants in HEPACAM alter hepaCAM protein function in vivo and facilitate MLC pathogenesis during brain development remain largely unknown. Here, we used new viral tools and proximity-based proteomics to examine how three different dominant pathogenic variants alter hepaCAM subcellular localization and protein interactome in astrocytes of the developing mouse cortex. We found dramatic changes in hepaCAM distribution throughout the astrocyte, which were common to all mutants tested. We also observed significant changes in protein interactome between wild type and mutant hepaCAM, including decreased association with previously described hepaCAM-interacting proteins Connexin 43 and CLC-2. Moreover, we identified the epilepsy-associate potassium channel KCNQ2 as a novel hepaCAM interaction partner and found reduced association between KCNQ2 and pathogenic variants. Collectively, our data provide new insights into hepaCAM protein function in astrocytes during brain development, reveal altered protein dynamics of pathogenic variants, and provide a new resource to explore the molecular underpinnings of MLC pathogenesis.

Animals↗
PubMed2026

Pre-treatment polyfunctionality percentage (PFA) of CD8+ T cells is associated with development of immune-related adverse events (irAEs) in patients receiving immune checkpoint inhibitors (ICIs).

INTRODUCTION: Immune checkpoint inhibitors (ICIs) have improved cancer survival, but immune-related adverse events (irAEs) occur frequently and can have devastating consequences. There are no validated methods to evaluate risk of irAEs prior to initiation of ICIs. MATERIALS AND METHODS: We conducted a pilot study evaluating the ability of blood-based, single-cell secretomic analysis to characterize irAEs. A total of 10 patients with thoracic malignancies who were scheduled to receive ICIs were enrolled. Each patient had a pre-ICI blood sample drawn as well as a sample at the time of irAE development or 12 weeks after ICI initiation, whichever came first. Utilizing IsoPlexis's IsoLight system, polyfunctionality percentages (PFAs) and strength indices (PSIs) were analyzed for CD4+ and CD8+ T cells. RESULTS: Five patients developed irAEs and 5 patients did not develop irAEs. Pre- and post-ICI CD8+ T cell PFA was significantly elevated in patients who developed irAEs compared with those who did not (p = 0.017 and p = 0.014, respectively). CONCLUSIONS: In this pilot study, pre-ICI CD8+ T cell PFA was associated with development of irAEs. While this is a pilot study, this is a first step toward developing a blood-based, streamlined assay to assess risk of irAEs prior to initiation of ICIs. Validation in larger cohorts is warranted.

Humans↗
PubMed2026

Estrone disrupts early reproductive development in juvenile male Siniperca chuatsi and is associated with brain and gonadal responses.

Whether estrone (E1)-associated disruption of early reproductive development in fish is accompanied by brain responses in addition to direct gonadal effects remains unclear. Here, juvenile Siniperca chuatsi, a non-model but economically important freshwater species, were exposed for 60 d to 0, 0.01, 0.1, and 1.0 μg/L E1, spanning environmentally reported and elevated concentrations. By integrating waterborne concentration monitoring, histopathology, transcriptomics, and quantitative real-time PCR (qPCR) validation, we evaluated E1-associated changes in brain and gonadal tissues during early reproductive development. Waterborne E1 concentrations remained generally stable throughout the exposure period. At the highest tested concentration (1.0 μg/L), E1 caused neuronal vacuolation and pyknosis in the hypothalamic region and induced distinct ovarian-like structures in the gonads of genetic males. In the brain, cyp19a1, crhr1, and adcy2a were significantly upregulated, whereas egr1 was significantly downregulated, indicating transcriptional changes in genes associated with local estrogen conversion, stress-response/cAMP signaling, and neuronal activity-related regulation within a broader injury/stress-response background. In the gonad, RNA-seq analysis showed significant downregulation of star2, hsd3b1, cyp17a1, and cyp11b and significant upregulation of hsd17b1, suggesting alterations in steroidogenesis-related gene expression at the transcriptomic level. qPCR analysis of selected gonadal candidate genes showed expression directions generally consistent with the RNA-seq results, and these molecular patterns were consistent with the feminized histological phenotype. Together, these results indicate that E1 can disrupt early reproductive development in juvenile S. chuatsi and support a cautious working model in which E1 exposure is accompanied by concurrent brain and gonadal responses. This study provides new evidence for understanding the toxic effects and ecological risk implications of natural estrogen E1 during early fish development.

Animals↗
PubMed2026

Comprehensive identification and evolutionary analysis of the Wnt gene family in bivalves: Insights into the larval development of the noble scallop Chlamys nobilis.

The Wnt gene family regulates fundamental developmental processes in metazoans, but its evolutionary composition and developmental deployment in bivalves remain largely unresolved. Here, we performed a comparative genomic analysis of Wnt genes in 19 bivalve species and examined developmental expression profiles in the noble scallop Chlamys nobilis, with Crassostrea gigas and Chlamys farreri used for cross-species comparison. A total of 235 Wnt genes were identified and assigned to 12 subfamilies. No reliable Wnt3 ortholog was detected in any analyzed bivalve, supporting the view that Wnt3 loss occurred early during lophotrochozoan evolution rather than representing a lineage-specific absence. Most Wnt proteins retained the conserved WNT domain, indicating strong structural conservation, whereas lineage-specific copy-number variation and gene loss were observed among species. C. farreri and C. gigas each retained 12 Wnt genes and lacked Wnt3, whereas C. nobilis lacked Wnt3, Wnt7, and Wnt16. Developmental transcriptome analysis and RT-qPCR revealed clear stage-specific expression patterns. In C. gigas, Wnt2/10/A were highly expressed during earlydevelopment and peaked around the D-shaped larval stage, while Wnt8 and Wnt11 showed distinct stage-specific peaks. By contrast, Wnt1/5/6/9 were more active during later larval development or juvenile formation. These results provide a comparative framework for bivalve Wnt evolution and identify candidate Wnt genes potentially involved in larval development and aquaculture-relevant developmental transitions.

Animals↗